Chemical analysis using Atomic Emission Spectroscopy (AES) uses the intensity of light at a specific wavelength emitted by a flame, plasma, arc or spark to determine the quantity of an element in a sample. The element's identity is revealed by the wavelength of the atomic spectral line in the emission spectrum, and the intensity of the emitted light is proportional to the element's number of atoms. There are a variety of ways the sample can be excited. An analyte sample can be directly inserted into the flame by means of a small loop of platinum wire, or it can be sprayed into the flame as a gas. The solvent is evaporated and intramolecular bonds are broken by the flame's heat to produce free atoms. The atoms are also excited into excited electronic states by the thermal energy, which cause them to return to the ground electronic state and produce light. The spectrometer measures the light that is scattered by a grating or prism and is emitted by each element at a specific wavelength. Lasers are increasingly being used as probes and even to start and change many different reactions. Analytical chemistry's application to forensic, environmental, industrial, and medical problems, like histology, grew significantly in the latter part of the 20th century. Instrumental analysis dominates modern analytical chemistry. Utilizing inductively coupled plasma, Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) generates excited atoms and ions that emit electromagnetic radiation at wavelengths characteristic of a specific element. ICP-AES has many advantages, including a stable and repeatable signal, multi-element capability, low chemical interference, an excellent limit of detection and a linear dynamic range. Spectral interferences (many emission lines), operating expenses, and the requirement that samples typically be in a liquid solution are disadvantages. An induction coil and plasma make up the emission source known as an Inductively Coupled Plasma (ICP). An alternating current-flowing wire coil is known as an induction coil. A magnetic field is created inside the coil by this current, which transfers a lot of energy to plasma in a quartz tube inside the coil.

Plasma is made up of cations and electrons, charged particles that can interact with a magnetic field because of their charge. Ionization of an argon gas stream results in the formation of the plasmas used in atomic emissions. As the charged particles move through the gas, resistive heating causes plasma to reach a high temperature. Plasmas have a higher population of excited states and better atomization because they operate at temperatures much higher than flames. Currently, a liquid sample is the most common type of sample matrix used in ICP-AES: Solids digested into aqueous forms or acidified water using a peristaltic pump, liquid samples are pumped into the nebulizer and sample chamber. After that, the samples go through a nebulizer, which sprays liquid particles in a fine mist. While finer water droplets move with the argon flow and enter the plasma, larger water droplets condense on the sides of the spray chamber and are evacuated through the drain. Direct analysis of solid samples is possible with plasma emission. Glow-discharge vaporization, laser and spark ablation, and electro thermal vaporization are among these methods.

With Regards,
Joseph Kent
Journal Manager
Journal of Der Chemica Sinica